SERUM
Yes, SERUM was the Wordle answer on April 2, 2024 (Wordle #1018).
As an opener, it rules out about 94.2% of possible answers.
Meaning and pronunciation
Pronunciation: /ˈsɪəɹəm//ˈsiːɹəm//ˈsɪɹəm/
- Noun
-
Ellipsis of blood serum.
- Noun
-
Blood serum used as a blood product, in the practice of medicine: blood serum from the tissues of immunized animals (human or nonhuman), containing antibodies and used to transfer immunity to another individual (human or nonhuman).
Source: Wiktionary contributors · CC BY-SA 4.0. Corrections.
Wordle status
A word can be a playable guess without being a possible answer.
Playable guess
YesIncluded in the Wordle guess list used by our tools.
Possible answer
YesIncluded among the answers considered by the solver.
Past Wordle answer
Used oncePast Wordle answer: April 2, 2024 (#1018).
See the full page for that puzzle: April 2, 2024 (#1018).
The possible-answer list is the solver's current list and may change when Wordle adds new answers.
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See what the public sample says →How SERUM performs as a guess
SERUM is a possible answer, so it would solve about one game in 2,374 when every answer is treated as equally likely.
Played as an opener, it lands at least one colored tile in 84.9% of games, misses completely in 15.1%, and leaves about 138 possible answers on average.
In the previous complete opener benchmark, it ranks #4,262 of 14,855 openers, averaging 3.66 guesses in games solved within six turns.
Try your feedback pattern
Tap the tiles to match your feedback, then see the ranked follow-up guesses.
Useful pattern pages
If you only know part of the word, start with one of these matching patterns.
First-turn measures
All four describe SERUM used as an opening guess. Entropy is the same idea as “avg ruled out” on a log scale: a higher number means the guess splits the possible answers into more, smaller groups.
As an opening guess: previous benchmark
How SERUM performed in the previous complete opener benchmark, against its captured answer snapshot. These research figures are separate from today's solver recommendations. See the data page for the method.
Composition
Feedback chances
Example solver route
One example route used by the solver.
This solver benchmark reaches SERUM in 3 guesses.
Feedback distribution
SERUM can come back 111 different ways. These are the most likely, and how many of the possible answers give each one:
Letter-value totals
Base letter-value totals for SERUM; these do not show whether either game accepts the word.
Scrabble
Words With Friends
Scores shown are base values without double/triple letter or word bonuses.
Try next
Strategy after playing SERUM
What the solver recommends next for each way the board can respond to SERUM.
Quick reference
Largest feedback groups after playing SERUM:
Research on SERUM
Game-tree analysis and word research for SERUM, with an explanation for each figure.
Optimal play
Opening with SERUM, a proven-optimal strategy averages 3.68 guesses and ranks #3,475 of 14,855 legal openers. The best proven opener, TARSE, averages 3.55.
In hard mode it averages 3.83 guesses at best and is rank #2,225 of the 7,453 openers that can still guarantee a solve within six guesses.
Our six-turn simulation says 3.66, at or below the proven-optimal 3.68, because the two figures score different answer lists.
These figures come from exhaustive game-tree search and are exact for the NYT lists of July 2023 (3,158 answers). They do not use the site's working answer pool.
How it sounds
Two syllables, stress on the first syllable Say it SIHRUHM.
Related meanings
In WordNet's sense inventory, SERUM is a kind of humor.
Familiarity and learning
- Frequency
- SERUM sits in the intermediate band of the wordfreq scale, appearing about 5 times per million words of written English; the band marks it as a word most readers meet regularly.
- Dominant sense
- Lancaster raters associated it most strongly with sight (2.8 of 5).
In a sentence
Lukas really had the serum.
Lukas didn't get the serum.
Sources: Optimal-play values: Alex Selby's exhaustive Wordle analysis (MIT); Pronunciation: CMU Pronouncing Dictionary (BSD); Word relations: Open English WordNet, 2025 edition (CC BY 4.0); Word frequency: wordfreq (data CC BY-SA 4.0); Lancaster Sensorimotor Norms (CC BY 4.0).